Bacillus cereus that lives in the soil propagates in starch-based foods such as rice, pilaf and spaghetti, and produces cereulide that induces an emetic action on an animal such as human. It is also known that not all Bacillus cereus species produce cereulide, but only Bacillus cereus species which acquire a cereulide synthetic gene produce this toxic substance.
Currently, when food poisoning by cereulide is suspected, a method for identifying cereulide in an extract of the food by HPLC or LC/MS is carried out. There is also a method for carrying out bioassay using cells, using a vacuolating action of cereulide as an index.
It is known that such cereulide has high heat resistance, acid resistance, and resistance to digestive enzymes, is not deactivated in the process of cooking and digestion, and acts on the small intestine nervous system to induce vomiting phenomenon. Furthermore, liver damage, mitochondrial toxicity, induction of alteration of cellular morphology, apoptosis induction and the like are reported, but researches of molecular mechanism of the vomiting phenomenon or other toxicity at a molecular level have not made any progress.
For the determination of food poisoning, methods by detection of a synthetic enzyme gene in a specimen (Patent Documents 1 and 2) are also suggested.
However, development of a simple analysis method, not a method requiring an expensive analytical instrument and skilled technique, is desirable.
For qualitative or quantitative analysis for determining food poisoning due to cereulide, as well as toxicity evaluation or elucidation of the mechanism at a cellular or molecular level, a pure cereulide reference standard is often required.
Currently commercially available cereulide is extracted from a culture solution of Bacillus cereus, and is available as a methanol solution of cereulide.
As a method for obtaining such cereulide, methods for synthesizing cereulide and a derivative thereof are also suggested (Non-Patent Documents 1 and 2).